[PATCH v14 2/5] dma-buf: heaps: Add heap helpers

[John Stultz]

On Mon, Nov 4, 2019 at 11:34 AM John Stultz <john.stultz at linaro.org> wrote:
>
> On Sun, Nov 3, 2019 at 8:13 AM <sspatil at google.com> wrote:
> > On Fri, Nov 01, 2019 at 09:42:35PM +0000, John Stultz wrote:
> > > Add generic helper dmabuf ops for dma heaps, so we can reduce
> > > the amount of duplicative code for the exported dmabufs.
> > >
> > > This code is an evolution of the Android ION implementation, so
> > > thanks to its original authors and maintainters:
> > >   Rebecca Schultz Zavin, Colin Cross, Laura Abbott, and others!
> > >
> > > Cc: Laura Abbott <labbott at redhat.com>
> > > Cc: Benjamin Gaignard <benjamin.gaignard at linaro.org>
> > > Cc: Sumit Semwal <sumit.semwal at linaro.org>
> > > Cc: Liam Mark <lmark at codeaurora.org>
> > > Cc: Pratik Patel <pratikp at codeaurora.org>
> > > Cc: Brian Starkey <Brian.Starkey at arm.com>
> > > Cc: Vincent Donnefort <Vincent.Donnefort at arm.com>
> > > Cc: Sudipto Paul <Sudipto.Paul at arm.com>
> > > Cc: Andrew F. Davis <afd at ti.com>
> > > Cc: Christoph Hellwig <hch at infradead.org>
> > > Cc: Chenbo Feng <fengc at google.com>
> > > Cc: Alistair Strachan <astrachan at google.com>
> > > Cc: Hridya Valsaraju <hridya at google.com>
> > > Cc: Sandeep Patil <sspatil at google.com>
> > > Cc: Hillf Danton <hdanton at sina.com>
> > > Cc: Dave Airlie <airlied at gmail.com>
> > > Cc: dri-devel at lists.freedesktop.org
> > > Reviewed-by: Benjamin Gaignard <benjamin.gaignard at linaro.org>
> > > Reviewed-by: Brian Starkey <brian.starkey at arm.com>
> > > Acked-by: Laura Abbott <labbott at redhat.com>
> > > Tested-by: Ayan Kumar Halder <ayan.halder at arm.com>
> > > Signed-off-by: John Stultz <john.stultz at linaro.org>
> >
> > I have one question and a naming suggestin below (sorry).
> >
> > Acked-by: Sandeep Patil <sspatil at android.com>
>
> > > +
> > > +static void dma_heap_buffer_vmap_put(struct heap_helper_buffer *buffer)
> > > +{
> > > +     if (!--buffer->vmap_cnt) {
> >
> > nit: just checking here cause I don't know the order in which vmap_get() and
> > vmap_put() is expected to be called from dmabuf, the manual refcounting
> > based map/unmap is ok?
> >
> > I know ion had this for a while and it worked fine over the years, but I
> > don't know if anybody saw any issues with it.

Sorry, I hit send before replying to this bit. I'll double check on this.

thanks again for the review!
-john